Cement compositions are used in the oil and gas industry to cement the annular space in the well bore between the surrounding formation and the pipe or casing. Typically, the cement slurry is pumped down inside of the casing and back up the outside of the casing through the annular space. The amount of water that is used in forming the cement slurry varies depending upon the type of hydraulic cement selected and the job conditions at hand. The amount of water used can vary over a wide range, depending upon such factors as the required consistency of the slurry, the necessary density for the control of formation pressures, and upon the strength requirement for the particular job.
Many times the hydraulic cement must be placed within or next to a porous medium such as, for example, earthen strata in the well bore. When this happens, water tends to filter out of the slurry and into the strata during the setting of the cement. Many difficulties are related to an uncontrolled fluid loss of this type, such as uncontrolled setting rate, improper placement of the slurry, impaired strength properties, and contamination of the surrounding strata. These conditions are all undesirable in oil and gas well cementing operations.
Therefore, there is an ever-present need to develop a process for controlling the fluid loss of a cement composition. Controlling fluid loss of a cement composition can also improve the curability of the composition.